Practical Antibiotic Prescribing & Antibiotic Awareness

1. Practical Antibiotic Prescribing & Antibiotic Awareness Berny Baretto (Antibiotic Pharmacist) 21st November 2013

2. Contents • Antibiotic Awareness Day-18th November 2013 • How to prescribe an antibiotic • Why is it important? • Background • Audit • What must be included in an antibiotic prescription • Practical examples • Gentamicin Prescribing • Summary

3. European Antibiotic Awareness Day- campaign to promote prudent antibiotic use(supported by DOH)

4. European Antibiotic Awareness Day 18 November 2013

5. Key Messages • It is a public health initiative aimed at encouraging responsible use of antibiotics • Lack of new antibiotics being developed especially to cover gram negative bacteria. • Number of infections due to antibiotic–resistant bacteria is growing • Important to preserve the use of the antibiotics currently available eg carbapenems

6. Background contd-Use selects Resistance • Acquired resistance absent from bacteria collected pre-1940 • Resistance repeatedly followed introduction of new antibiotics • Resistance greatest where use heaviest • Resistant mutants selected in therapy

7. Β-Lactam use & resistance in S.pneumoniae → Low rates of antibiotic use = low resistance Bronzwaer et al Emerg Infect Dis. 2002; 8:278-82

8. How to prescribe an antibiotic –why is it important • Department of Health Guidelines-(Advisory Committee on antimicrobial resistance and healthcare associated Infection)-Nov 2011 • Antimicrobial stewardship- “start smart-then focus”- • Want : • Right Drug • Right Dose • Right Time • Right Duration • For Every Patient

9. Start Smart Is : • Don’t start antibiotics in the absence of clinical evidence of bacterial infection • If there is evidence or suspicion of bacterial infection-use local antibiotic guidelines to start treatment • Document on drug chart Indication, duration/review date, route & dose • Obtain cultures first • Prescribe single dose antibiotics for surgical prophylaxis-where proven efficacy

10. Then Focus is: • Review clinical diagnosis and the coninuing need for antibiotics by 48 hours and make a clear plan of action- “the antimicrobial prescribing decision” • 5 options • 1. STOP • 2. Switch i/v to oral • 3. Change –ideally to narrower spectrum or broad if needed • 4. Continue (review again at 72 hours) • 5. Outpatient Parenteral antibiotics therapy (OPAT) • Make sure review and decision is clearly documented in medical notes.

11. Department of Health Guidance-Antibiotic Stewardship

12. Good Prescribing Practice • Promotes Good Prescribing Practice- no missed doses, ensures continuity in care • Adherence to Trust Antibiotic Policy • Helps to Reduce Incidence of Clostridium difficile Infection • Audit

13. Quarterly Audit-(overall Trust Data)

14. Specific Antibiotic Monitoring

15. PRACTICAL EXAMPLES

16. What must be included in an antibiotic prescription-Documentation of allergy status

17. UTI Recommendation

18. Uncomplicated Cystitis

19. Crossing off an Antibiotic

20. Re-prescribing after antibiotic sensitivities appear on CRRS

21. Chest Infection Recommendation

22. Query Non-severe CAP

23. Gentamicin Prescribing • 5 steps for safe gentamicin prescribing • Usually gentamicin is only required for 24-48hrs. • Course lengths for gentamicin should not exceed 5 days unless Microbiology have approved its use for extended durations (this may be indicated in some infections eg Endocarditis).

24. 1. Weigh Patient: • Weigh patient. If weighing is not possible, estimate weight using ideal body weight formulae (based on height and gender). • For obese patients >120% ideal body weight use formula for dosing weight.-see below.

25. Equations for Ideal Body weight and Obese dosing • Imperial • Ideal Body weight (Male) = 50 + (2.3 x inches over 5 feet) • Ideal Body weight (Female) = 45.5 + (2.3 x inches over 5 feet) • Or • Metric • Ideal Body weight (Male) = 50kg + 0.9kg for each cm above 150cm in height • Ideal Body weight (Female) = 45.5Kg + 0.9kg for each cm above 150cm in height • For Obese Patients (> 120% of ideal body weight) use obese dosing weight calculation5 : • Obese Dosing Weight (in Kg) = ideal body weight + 0.4 (actual Body weight – ideal body weight)

26. 2. Calculate gentamicin Dose : • Calculate the gentamicin dose using 5mg/Kg (maximum 400mg od) • a)If normal body weight - use actual body weight value • b)If Obese (> 120% of ideal body weight)- use obese dosing weight • c) if weight unobtainable – calculate ideal body weight

27. 3. Calculate creatinine clearance (CrCl) : • Calculate the creatinine clearance using Cockcroft and Gault equation • Creatinine = (140-age in years) x weight in Kg(from step 1) x F • clearance Serum Creatinine (in micromole/Litre) • F=1.04 (female) or F=1.23 (male)

28. 4. Check dosing Interval and when levels need to be done : Work out the dosing interval and when levels should be checked

29. 5. Check gentamicin serum level • If pre-dose gentamicin level is 1mg/L or less continue the original dosing regime • If pre-dose gentamicin level is greater than 1mg/L, consult Microbiology or Pharmacy for advice.

30. Documentation on Medicine Chart

31. SUMMARY • 1. Antibiotic Awareness • 2. What to include when prescribing an antibiotic-practical examples • 3. Why do we document this- The background • 4. Audit • 5. Gentamicin prescribing